In modern medicine and science there is a growing need for the ability to profile composition of such bodily fluids as serum and saliva. Microarray chip technology has potential for delivering such ability. This technology has already changed pharmaceutical research. So far, however, this technology has not been used extensively in protein-focused studies. The reason for this lies in the substantial diversity of protein properties. This diversity affects performance of protein arrays and, consequently, limits the number of analytes that can be simultaneously interrogated by such arrays. Our objective is to develop a set of interconnected protocols and constructs that will constitute a novel approach to protein array design. This approach will allow achieving more uniform efficiencies of: 1) attachment of probe proteins to the matrix of the array, 2) interaction between individual probes and corresponding proteins from the interrogating sample (analytes), and 3) visualization of individual interacting pairs. To achieve our objective we will combine advancements in the ligand-display technology and techniques for generation of chimera proteins with the emerging platform of particle-based flow cytometric assays. First, we intend to apply the developed approach to address the needs existing in the area of bioterrorism defense. Therefore, during Phase I we will demonstrate the feasibility of the approach by developing an array for detection of anti-botulinum serotype A antibodies. During Phase II, we will broaden the spectrum of antibodies detected by the system. We will incorporate into the array antigenic determinants for such pathogenic agents of concern in the field of bioterrorism as Bacillus anthracis, Clostridium botulinum (serotypes B, C and E), and ricin to create a tool for evaluation of the level of individual protection from potential bioterrorist attacks. [unreadable] [unreadable]